Extreme pressure lubricant



Patented Nov. 15, 1938 UNITED STATES PATENT OFFICE i v. M ],fi2,13s,sss

, it 1 EXTREMEBPRESSURE LUBRICANT Franz Rudolf Moser, Amsterdam, Netherlands, 1 and Marinus CornelisTuyn, Pladjoe, Netherlands East'Indies, assignors to Shell Development Company, San Francisco, Calif., a. cor- Y poration of Delaware NoDrawin g Application March 16, 1936; Serial 69,162. I n' the Netherlands March 19,

1 Claim. (01. 87-9) This invention relates to lubricants suitable for lubrication under extreme pressure conditions.

It is well known that the high pressures occurring in certain types of gears and bearings 5 may cause a film of lubricantto rupture with conscqucnt'damage to the,machinery; It hasbeen shown that mineral lubricating oils can be improved with regard to their load carrying capacity by, the addition ofcertain substances to a degree, which enables them to successfully resist being Completely forced out from between rubbingfsfirfaces under extreme pressures. Excessive wear, scufling and seizure, which jnerrnally follow a break in the filmpi lubricantcan thus be pre- 15 vented even undertthe most unfavourable pressure andspeed conditions. Oils. possessing this highly resistive property are called extreme pressure lubricants. a r Among the substances that have been proposed 2 for incorporation into the lubricating oils 'for the purpose of improving their extreme pressure properties, there is a class of oil-insolubles'olid compounds which by themselves can be used as lubricants in a limited way. Examples of this 2 class-of compounds are graphite, zinc oxide, lead sulfide, talc, clay; etc., all of which are being used in suspension of lubricating oils. We have now discovered another useful class of, substantially oil insoluble compounds, which bythemselves have little or no lubricating powers, but which are capable of improving the extreme pressure properties of mineral'lubricating ,oils. This class consists essentially of fairly high molecular weight organic substances I possessing several polar radicals such as -OH, COOH, --NH2, .=NH,- SH, S, =C= etc., and avhigh thermalfstability at least. equal. to. that of the minerallubricating oil to which the dope is added. Molecular weights range from about 200 40 to an upper unknown limit. I The com poundsare cyclic in structure, containing several rings, at leastpne of which is aromatic, In addition theycontain nitrogen usually in the-form of a derivative of an aromatic amino compound, and 5 most of them have the properties of dyes substantially insoluble in mineral oils, While some of these dyes are"solublein mineral oils to the extent of imparting color to the oil, their solubility is well below 0.1%. 50 The compounds of our invention have several advantages over other oil insoluble compounds used heretofore to impart extreme pressure properties to lubricating oils. Not only have our compounds a much greater effect than, for instance, the widely used graphite, but being of organic nature they produce no ash, and are therefore often preferable to some otherwise very useful substance, such as lead sulfide. Many of our compounds, being free from a tendency to 60 be corrosive or to liberate corrosive substances even at high temperatures andunder conditions,

encountered in crankcases of internal combustion engines while in" operation, can be safely incorporated into lubricants used. in internal combustion engines, so that the preparation of safe crankcase oils possessing "extreme pressure prop-:=

erties has now been madepossible. The quan-- titles of our compounds required to impart extreme pressure properties usually vary from about 0.1 to %.by weight; and must be in excess of the solubility limit of the compounds in the lubrieating oils.

Particular substances which are useful for our invention are i Anthraquinone derivatives. such as: I

Indsnthmne Hydroxy derivatives or indanthrene Flavanthrene on-o -0 00 Am and diaae compounds mm-mdhmmmumxnm) Newma- Naomi. "mile, W by one-an OI aniline ON ON-OM 0: NHCIHNHI eo I'remthepointotviewoi'thermalstability many of the anthraquinone derivatives are of particular value.

Most commercially available dyes contain considerable proportions of inorganic impurities, usually sodium chloride, which of course is extremely harmful in lubricating oils and must be removed. for instance by washing with water, prior to blending with the oil.

The process oi admixing the compounds of our invention to lubricating oils may be carried out according to known principles. The powdered compounds may simply be stirred into the oil, or a stock suspension may be prepared by running a rich mixture of compounds in oil through a colloid mill, and then admixing some of the stock suspension to lubricating oils.

' Sometimes it may be desirable to introduce peptizing agents to prevent the compounds from settling; anticorrosion agents may be 01' advantage in combinations with certain compounds which have a corrosive tendency, for instance tetraao m-phenylene dlamine chlorhydrate, or mercaptobenzthlazol. Antioxidants may be used to prevent the premature oxidation of some of the additions.

In the following illustrative examples the eil'ects on the illm strength of a lubricating oil due to the addition of some of the above de scribed compound is shown. The four-ball apparatus by Boerlage, which was described in Engineer-mg" vol. 136 (1933) page 46 was used for testing; this apparatus is capable of measuring the comparative metal wear at various pressures, as well as the pressures at which the test metals weld in the presence of the test lubricant.

The data below are typical:

Percent Welding Diameter of Substance added by pressure wearing surface in mm.

2.2 at 100 kg.

2.63 at 600 kg.

2.10 at 260 kg.

2.2 at 350 kg- 11) at 600 kg.

1.86 at 400 kg.

2.07 at 250 kg.

vary considerably with the individual substance, the improvement in the lubricating property 01 the oil isquite great.

We claim as our invention:

An extreme pressure lubricant consisting essentially of a mineral lubricating oil containing not less than 0.1% finely divided nigraniline.

I mm armou mosaic.

mums coams Tom. 

